If the math is correct, these may require a good bit of power. I think most cellphones are gonna have a tough time pushing these to sound their best (kinda like the PX...). Since the specs state the sensitivity is 91 +/- 3 dB at 16 ohms:
For 88 dB/1 mW

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For 91 dB/1 mW

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I kept the output impedance at 1 ohm since that would be the most ideal. Mind that if your source has a higher output impedance and/or you listen as a slightly louder volume than 80 dB, you're going to need more power than what's listed here. Almost 2Vrms for an IEM is pretty demanding but I am curious how well these will sounds/scale out of a desktop amp.

True. This is a rough estimate just for context so folks have a gauge on how well their equipment will drive these. Hopefully when we get measurements we'll be alerted to any potential impedance/voltage swings and hopefully performance with higher output impedance (my amp/dac's is under 1 but my phone is closer to 5).

1) Most people listen well below 80dB. Use ReplayGain and you will likely have no problem hitting 80dB out of any modern smartphone.
2) Scaling with amplifiers is a myth, caused largely by placebo effects and failure to match volumes properly.

I don't disagree with any of that article (I'm pretty sure I've read that article before) -- 100% spot on. However, there's a very objective difference between between built-in amp in a phone and external amp. So we're not talking here $100 amp vs. $400 amp, we're talking about phone/power optimzed amp vs. discrete, wall-powered amps.
I was asking about the source for your number 1) that most people listen at 80 dB. That seems like rather arbitrary claim.

The "proof" you provided is a subjective piece with anecdotal evidence at best. Nothing about it is objective nor does it wholly pertain to the points you brought up. He spent most of the article bashing Headfonia because he doesn't agree with what the reviewer said about his equipment. He then proceeded to state how the reviewer is biased and apparently hears. That's some real objective detective work right there 🙄
When NwAvguy focuses just on measurements and discusses, I tend to trust and believe his knowledge more as it's just a matter of interpreting graphs, responses, etc. and equating what we see into what we hear. For these "opinion" pieces, he comes off as incredibly biased and incredulous. Like he has an axe to grind because the entire world doesn't believe what he does and they're all stupid for thinking anything else. Just outright pompous and arrogant. Here's just a taste:

"Questionable Gear - Some of the most hyped gear on Head-Fi, in my opinion, is snake oil—Audio-GD, NuForce and Schiit Audio are three examples arguably based on hype rather than solid engineering. Some of it is sold through very limited sales channels and Head-Fi is probably responsible for the majority of the sales."

For any of the points you presented, you don't have any factual, scientific evidence to backup your claims. It's all so subjective either way so I highly doubt there's any way to objectively prove otherwise.

The article talks about how the human perceptual system is flawed. You can go look at some of his other articles about amps to learn more about how they work and, by extension, why "scaling" is not really possible. He is far from perfect, but the information about perceptions in the article I linked is valid and relevant to the points I brought up about amp scaling. As for the hyped stuff being snake oil, he is not that far off. Schiit's multibit stuff is worse than their Delta-Sigma gear while costing more, and Audio-GD is also using NOS ladder DACs instead of modern, and superior, technology. Measurements from Audiosciencereview showed that the $2300 Yggdrasil could not manage to stay linear beyond 16 bits.

I've read quite a few of his articles as I stated above. The point is he cannot accurately state how much this "perception" sways an individuals thoughts and experiences. Honestly, it's all rather a moot point and still based off anecdotal evidence. It's not as if any of the studies were scientific tests that had true, measurable objectives.
How an amp works still doesn't address your bold statement that "an amp is an amp ." If that statement was even reasonably true, all low impedance IEMs that require only a couple of mW to get ear-shatteringly loud would sound the same from ANYTHING they get plugged into (a TV, phone, laptop, receiver, etc). Since these devices all can produce 1mW to push almost every IEM to 100+dB they should all theoretically sound and perform the same per your logic. Yet, we all know this isn't the case. You trying to oversimplify something as convoluted and subjective as someone's hearing and perception is misleading, at best.

I forgot to mention output impedance. Oops, I will fix that. I still stand by the claim that amps sound the same, provided they do not produce audible levels of distortion, have a flat frequency response within the audible range, and can produce an adequate damping factor.
I am not really oversimplifying. Perceptions are very prone to be inaccurate, especially when there is pressure to perceive something a certain way. Take burn-in for example: have you ever heard of someone complaining about headphone burn in? I have not once seen someone say that burning in their headphones made them worse. I have, however, seen people write about how burn-in transformed their headphones into devices that produce pure bliss. Burn in is just one example; there was a guy on reddit who claimed he could hear a difference between plastic and glass toslink cables, or the entire high resolution audio scam, or a good chunk of what gets Editor's Choice on Stereophile (see wathifi.com for more examples.). Here [https://www.cell.com/neuron/fulltext/S0896-6273(14)00192-5] is an article on how the placebo effect can alter perceptions of pain. If pain can be altered, why would perceptions of sound be immune to this? What else could explain people hearing what research says is not audible, but being unable to pass a blind test?